$(function(){
	
	

var headers = $("section > ul > li");
var bodys = $("section > div");

headers.each(function(index,element){
	$(this).on("click",function(){
		headers.each(function(){
			$(this).removeClass("active-header");
		});
		$(this).addClass("active-header");

		bodys.each(function(){
			$(this).css("display","none");
		});
		bodys.eq(index).css("display","block");
	});
});


(function(window,document){
    //定义画布宽高和生成点的个数
    var WIDTH = window.innerWidth, HEIGHT = window.innerHeight, POINT = 35;
    
    var canvas = document.getElementById('canvas');
    canvas.width = WIDTH,
    canvas.height = HEIGHT;
    var context = canvas.getContext('2d');
    context.strokeStyle = 'rgba(0,0,0,0.02)',
    context.strokeWidth = 1,
    context.fillStyle = 'rgba(0,0,0,0.05)';
    var circleArr = [];

    //线条：开始xy坐标，结束xy坐标，线条透明度
    function Line (x, y, _x, _y, o) {
        this.beginX = x,
        this.beginY = y,
        this.closeX = _x,
        this.closeY = _y,
        this.o = o;
    }
    //点：圆心xy坐标，半径，每帧移动xy的距离
    function Circle (x, y, r, moveX, moveY) {
        this.x = x,
        this.y = y,
        this.r = r,
        this.moveX = moveX,
        this.moveY = moveY;
    }
    //生成max和min之间的随机数
    function num (max, _min) {
        var min = arguments[1] || 0;
        return Math.floor(Math.random()*(max-min+1)+min);
    }
    // 绘制原点
    function drawCricle (cxt, x, y, r, moveX, moveY) {
        var circle = new Circle(x, y, r, moveX, moveY)
        cxt.beginPath()
        cxt.arc(circle.x, circle.y, circle.r, 0, 2*Math.PI)
        cxt.closePath()
        cxt.fill();
        return circle;
    }
    //绘制线条
    function drawLine (cxt, x, y, _x, _y, o) {
        var line = new Line(x, y, _x, _y, o)
        cxt.beginPath()
        cxt.strokeStyle = 'rgba(0,0,0,'+ o +')'
        cxt.moveTo(line.beginX, line.beginY)
        cxt.lineTo(line.closeX, line.closeY)
        cxt.closePath()
        cxt.stroke();

    }
    //初始化生成原点
    function init () {
        circleArr = [];
        for (var i = 0; i < POINT; i++) {
            circleArr.push(drawCricle(context, num(WIDTH), num(HEIGHT), num(15, 2), num(10, -10)/40, num(10, -10)/40));
        }
        draw();
    }

    //每帧绘制
    function draw () {
        context.clearRect(0,0,canvas.width, canvas.height);
        for (var i = 0; i < POINT; i++) {
            drawCricle(context, circleArr[i].x, circleArr[i].y, circleArr[i].r);
        }
        for (var i = 0; i < POINT; i++) {
            for (var j = 0; j < POINT; j++) {
                if (i + j < POINT) {
                    var A = Math.abs(circleArr[i+j].x - circleArr[i].x),
                        B = Math.abs(circleArr[i+j].y - circleArr[i].y);
                    var lineLength = Math.sqrt(A*A + B*B);
                    var C = 1/lineLength*7-0.009;
                    var lineOpacity = C > 0.03 ? 0.03 : C;
                    if (lineOpacity > 0) {
                        drawLine(context, circleArr[i].x, circleArr[i].y, circleArr[i+j].x, circleArr[i+j].y, lineOpacity);
                    }
                }
            }
        }
    }

    //调用执行
    init();
    setInterval(function () {
        for (var i = 0; i < POINT; i++) {
            var cir = circleArr[i];
            cir.x += cir.moveX;
            cir.y += cir.moveY;
            if (cir.x > WIDTH) cir.x = 0;
            else if (cir.x < 0) cir.x = WIDTH;
            if (cir.y > HEIGHT) cir.y = 0;
            else if (cir.y < 0) cir.y = HEIGHT;
            
        }
        draw();
    }, 16);
})(window,document);

	

});

